EVE-280Ah in 15S/1P w/ Batrium WM5

Hi Everyone,

Noob here, so don't hesitate to call out any stupidity. And my apologies in advance if this is already discussed elsewhere in the forum...I searched...I swear.

I'm in the process of designing an off-grid PV system for our farm. It seems that the 'grey-market' prismatic cells are an extremely cheap way to build a big bank, if you can manage the DIY part (and accept a bit of risk). My biggest concern with this approach is keeping things simple, safe, and reliable. For that reason, it seems like 'splurging' on a top-end, user-friendly BMS might be a good idea.

The new Batrium WatchMon5 (aka WatchmonPlus) seems like a great option (~$300 cheaper and way simpler than the WatchMon4+BlockMons), but it only supports up to 15 cell configurations. My questions is: is there any reason that a 15S x 3.2V bank won't work fine with most inverter/chargers? Seems like as long as the charge/discharge voltage settings on the inverter/charger are adjustable, it wouldn't make a difference, but I'm probably missing something.

Any other thoughts on running the EVE-280Ah cells in 15s/1P configuration with a Batrium WM5 would be greatly appreciated.

Jon

Pick a different bms.

But you are right, if the voltage range allow it to could. 16s is just for swapping out a lead acid system.

The system no one seems to have figured out yet is to take advantage of the communicating nature of the new batteries/inverters. THAT would be worth paying a bit for.

Actually what you propose seems really close to nominal for a replacement for a 48v flooded LA. 4 fully charged FLA batteries in series would sit at about 51.2v. Divide that by 15 and you get very close to 3.4v per cell, which is pretty close to fully charged for a LiFePO4 cell. You might have to avoid chargers that are not configurable and had aggressive LA voltage profiles.

15s is fine. The REC BMS was also 15s when it was first released. I know of one system that has been in use with this configuration with a SMA inverter for many years with no issues.

@zorlig the Batrium (and REC) have CANBUS comms with Victron and SMA inverters.

You need to build a 16 Cell battery for 48V which has more to do with the operating voltage curves under load.
There are many Good BMS' for reasonable prices. You need to define a few things before anyone can offer suggestions.

How many AMPS are you expected to pull from it (inverter size & loads)
How are you charging, how many amps available, what sources.
Is this mobile of residential.
What features do you need ? ie: Cold Temp cutoff
What features would you like ? Bluetooth, wifi, etc
Are you intending to integrate the BMS with the Solar / Inverter systems and or other equipment / monitoring systems?

Thanks so much for the quick replies!!!

Regarding my setup: I’m considering the new Phocos Any-Grid 5kw/120v inverter/charger combined with ~4,500 watts of panels. The Phocos has 80A MPPT, and I’ll have a Honda EU2200i hooked up as a backup charging source. Definitely need Low Temp cut-off (I’m in Wisconsin); would like to ‘integrate’ the BMS with the Phocos inverter via CANBUS to avoid external contactors. Ability to remote monitor would be very nice as well.

Zorlig, can you elaborate on your recommendation to avoid the WM5? Would you suggest the WM4, or avoid Batrium all together?

Thanks again!

Steve_S said:

You need to build a 16 Cell battery for 48V which has more to do with the operating voltage curves under load.

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You obviously haven’t dealt with a 15s LiFePO4 setup. A 400ah 15s pack is more than capable of running a 10kw peak inverter.

I've been running my backup system with an Outback VFX3648 with only 15 cells for a couple years and haven't noticed issues with it. Originally purchased 16 used cells but one of them was bad but the system has been working fine with only the 15.

rhino said:

I've been running my backup system with an Outback VFX3648 with only 15 cells for a couple years and haven't noticed issues with it. Originally purchased 16 used cells but one of them was bad but the system has been working fine with only the 15.

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Thanks for sharing your experience rhino.

Seems like 15s is likely to be fine, but based on some of the other responses, I decided to look elsewhere. I ended up purchasing a TinyBMS for the project. A bit cheaper than the Batrium after adding all the goodies (LEM sensor, USB cable, CAN converter, etc), but offers 16s and some other functionality that I'm interested to try out.

schroederjd said:

Thanks for sharing your experience rhino.

Seems like 15s is likely to be fine, but based on some of the other responses, I decided to look elsewhere. I ended up purchasing a TinyBMS for the project. A bit cheaper than the Batrium after adding all the goodies (LEM sensor, USB cable, CAN converter, etc), but offers 16s and some other functionality that I'm interested to try out.

Click to expand...

Did you go with the Batrium? Did 15S work ok for you?

FilterGuy said:

Did you go with the Batrium? Did 15S work ok for you?

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No, I went with the TinyBMS s516 in a 16s configuration. I’m running in separate port mode with external relays for charge and discharge. Charge relays are 200V/40A on the PV in lines, and discharge relays are 80V/5A wired in line with the inverter switches on/off switches. Now that I’ve got everything hooked up, I’m glad I didn’t go 15s, as I think my inverters (pair of Growatt SFP 3000 48P’s) may have objected to the lower voltage.